Response of red blood cell folate to intervention: implications for folate recommendations for the prevention of neural tube defects

Dietary folic acid intake, 13 genetic variants and other factors with red blood cell folate concentration in pregnancy-preparing population

PURPOSE

This study aims to evaluate a combined effect of dietary folic acid intake, multiple genetic polymorphisms in folate metabolism, and other environmental factors on red blood cell (RBC) folate concentration in pregnancy-preparing population.

METHODS

519 pregnancy-preparing subjects (260 couples) were investigated. Dietary intake was measured by 3-day dietary recalls. 13 Single Nucleotide polymorphisms (SNPs) reported in association with one-carbon metabolism including the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C were genotyped. RBC folate concentration was measured using chemiluminescence assay. Hierarchical regression was applied for covariate selection. Factors showed significance(p < 0.0125) on RBC folate level was included for prediction model construction and R2 estimation. Validation cohort analysis was performed as post-hoc analysis if applicable.

RESULTS

The median RBC folate was 212.8 ng/ml. Only 10% took folic acid supplementation within three months. Based on hierarchical selection, folic acid supplementation, genetic polymorphism (especially TT genotype of MTHFR C677T), serum folate level were determinants of the variance of RBC folate concentrations, with adjusted R2 of 0.178-0.242. MTHFR A1298C polymorphism, sex difference with other socio-demographic and lifestyle factors (age, BMI, alcohol drinking, smoking, education, occupation) explained little to change in RBC folate level. Validation in another sub-cohort(n = 8105) had adjusted R2 of 0.273.

CONCLUSION

In pregnancy-preparing subjects, folic acid supplementation, serum folate level and TT allele of MTHFR C677T polymorphism were determinants of the total variance of RBC folate level, which explained 19.8% variance in our subjects and 27.3% in the validation cohort. Food folate intake, sex and other environmental factors explained little to RBC folate level.

Folate Deficiency and Anemia Among Women of Reproductive Age (15-49 Years) in Senegal: Results of a National Cross-Sectional Survey

Background:

Widely spread throughout the world, folate and iron deficiencies are risk factors for many diseases. However, contrary to iron deficiency and anemia, which have been documented in depth, the prevalence of folate deficiency among women has not been well-studied.

Objective:

The aim of this study is to determine the prevalence of folate deficiency and anemia and their association among Senegalese women of reproductive age.

Methods:

A national cross-sectional survey using a stratified 2-stage cluster sampling was conducted. Data were collected from 1012 women (aged 15-49 years). Plasma folate and hemoglobin (Hb), as well as protein markers of subclinical infections, were equally measured.

Results:

The mean folate concentration was 8.50 nmol/L (8.16-8.85 nmol/L), and 54.8% of the women were folate deficient (<10 nmol/L). Plasma folate concentration of rural women (7.27 nmol/L [6.89-7.68 nmol/L]) and urban women (10.45 nmol/L [9.88-11.05 nmol/L]) was significantly different ( P < .0001), the highest concentration being observed in women living in Dakar, the capital of Senegal. The breastfeeding women showed lower plasma folate concentration compared to nonbreastfeeding ones: 6.97 nmol/L (6.37-7.63 nmol/L) versus 9.03 nmol/L (8.61-9.46 nmol/L). Overall, 27% of the women were suffering from inflammation/infections. Mean Hb concentration was 116.86 (1.18) g/L, and 47.63% of the women involved in the study were anemic (pregnant women Hb <110 g/L; nonpregnant Hb <120 g/L). Also, a positive and significant correlation was found between plasma folate and Hb concentrations ( r = .07; P = .0167).

Conclusions:

This study showed a high prevalence of folate deficiency and anemia among Senegalese women (15-49 years), particularly those living in rural settings and breastfeeding women.

Spinal cord malformations

Malformations of the spinal cord are one of the most frequent malformations. They should be clearly divided into two completely different families of malformations: open dysraphisms and occult dysraphisms. Open dysraphism mostly consists in myelomeningocele (MMC). Its incidence is 1/1000 live births with a wide variation. Folic acid supplementation has been shown to reduce its risk. In most cases, the diagnosis is done prenatally by serum screening and ultrasound and may lead to termination of pregnancy. In case of decision to continue pregnancy, surgical treatment must be achieved during the first days of life, and in 50 to 90% of cases, a ventricular shunt must be installed. The follow-up of these children must be continued throughout life looking for late complications (Chiari II and syringomyelia, vertebral problems, neuropathic bladder, tethered cord). Occult dysraphisms are a heterogeneous group of malformations. Lipomas (filum and conus) are the most frequent and their treatment remains controversial. Diastematomyelia, neurenteric cysts, dermal sinus, and more complex forms (Currarino syndrome) belong to this group. Most of them can and must be diagnosed prenatally or at birth by careful examination of the lower back for the cutaneous stigmata of the disease to decrease the risk of neurological, urological, or orthopedic permanent handicap.

Infant birth size is not associated with maternal intake and status of folate during the second trimester in Norwegian pregnant women

Maternal folate status and smoking are potentially strong risk factors for infant birth size. We assessed the association of several folate indicators and smoking with birth outcomes in a subsample of participants in the Norwegian Mother and Child Cohort Study, consisting of 2934 singleton pregnancies in 2002-2003. Blood plasma folate and cotinine concentrations and self-reported intake of food folate and supplemental folic acid were measured during the second trimester (median 18 wk). Birth outcomes included gestational age, infant birth weight, head circumference, crown-heel length, and small for gestational age (SGA). Mean total dietary folate intake from foods (mean 268.0 microg/d) and supplements (mean 187.7 microg/d) was 455.7 microg/d. Smokers (plasma cotinine > or = 85 nmol/L) had substantially lower supplemental folic acid intake than nonsmokers, but they did not differ regarding folate intake from food only. Nevertheless, smoking was correlated with plasma folate both before and after adjusting for total dietary folate intake (both P < 0.001). We found no significant associations of food folate intake, supplemental folic acid use, total dietary folate intake, or plasma folate with the various birth outcomes after adjustment for potential confounders. Consistent with previous studies, infant birth size was strongly predicted by maternal smoking (adjusted odds ratio for SGA: 2.3; 95% CI: 1.6, 3.3). This study of well-nourished Norwegian pregnant women suggests that dietary folate and plasma folate during the second trimester are not risk factors for infant birth size.

Steady state folate concentrations achieved with 5 compared with 1.1 mg folic acid supplementation among women of childbearing age

BACKGROUND

Synthetic folic acid (0.4-1.0 mg) consumed during the periconceptional period has been shown to reduce the risk of neural tube defects. Women with poor supplement adherence or a previous pregnancy affected by a neural tube defect may need to take higher doses of folic acid (4-5 mg). However, there are limited data on the pharmacokinetics of higher folic acid doses.

OBJECTIVE

Our aim was to compare steady state folate concentrations in women of childbearing age who took 5 or 1.1 mg folic acid daily for 30 wk.

DESIGN

Forty nonpregnant women aged between 18 and 45 y, who did not take folic acid supplements, were enrolled in the study. Subjects were randomly assigned to take either 5 or 1.1 mg folic acid daily for 30 wk. Plasma and red blood cell (RBC) folate concentrations were measured at baseline and at weeks 2, 4, 6, 12, and 30.

RESULTS

There was no significant difference in baseline RBC folate concentrations between the 2 groups (1121 +/- 410 and 1035 +/- 273 nmol/L for the 5- and 1.1-mg folic acid groups, respectively). Significant differences in RBC folate were detected between groups at weeks 4, 6, 12, and 30. RBC folate concentrations by week 30 were 2339 +/- 782 and 1625 +/- 339 nmol/L for the 5- and 1.1-mg folic acid groups, respectively.

CONCLUSION

The use of 5 mg folic acid among women of childbearing age produced higher blood folate concentrations, with a faster rate of folate accumulation, compared with 1.1 mg folic acid.

Dietary folate intake, blood folate status, and urinary folate catabolite excretion in Korean women of childbearing age

This study assessed folate intake, folate concentrations in plasma and erythrocytes, plasma total homocysteine (tHcy) concentrations, and urinary excretion of folate metabolites in Korean women of childbearing age. A total of 36 women voluntarily participated in this study. Precise dietary intake for 3 consecutive days was determined by weighing all foods consumed, and folate intake was calculated with a computer-aided dietary analysis system. Folate concentrations in plasma and erythrocytes were determined via microbiological methods and in plasma by HPLC. Urine excreted over the same period of time was collected and assayed for folate catabolites, para-aminobenzoylglutamate (pABG) and para-acetamidobenzoylglutamate (ApABG) by reverse-phase HPLC after affinity chromatography. The mean folate intake was 206.9+/-90.8 microg DFE/d, and the mean concentrations in plasma and erythrocytes were 10.5+/-3.7 and 249.9+/-77.8 ng/mL, respectively. Erythrocyte folate concentration was low in 2.8% of the subjects (<140 ng/mL) and was marginal in 5.5% (140-156 ng/mL). The mean plasma tHcy concentration was 12.7+/-0.2 nmol/mL, and 11% of the subjects evidenced hyperhomocysteinemia (>or=15 nmol/mL). The mean urinary excretion levels of pABG and ApABG were 10.7+/-3.8 and 89.1+/-19.5 nmol/d, respectively. The means of folate reserve and folate turnover rate were 26.2+/-11.6 and 10.5+/-3.9, respectively. We noted positive relationships between folate intake and the folate concentrations in plasma and erythrocytes, as well as the urinary excretions of ApABG and total folate catabolites. In addition, the erythrocytic folate concentrations were positively associated with the urinary excretions of ApABG and total folate catabolites. In conclusion, the folate status of Korean women of childbearing age was marginally deficient with inadequate concentrations of erythrocyte folate and elevated plasma tHcy, largely due to insufficient folate intake. The marginally deficient folate status was confirmed by the low excretion of folate catabolites in urine.

Chapter 30: historical aspects of the major neurological vitamin deficiency disorders: the water-soluble B vitamins

This historical review addresses major neurological disorders associated with deficiencies of water-soluble B vitamins: beriberi, Wernicke-Korsakoff syndrome, pellagra, neural tube defects, and subacute combined degeneration of the spinal cord. Beriberi: Beriberi was known for millennia in Asia, but was not described by a European until the 17th century when Brontius in the Dutch East Indies reported the progressive sensorimotor polyneuropathy. The prevalence of beriberi increased greatly in Asia with a change in the milling process for rice in the late 19th century. In the 1880s, Takaki demonstrated the benefits of dietary modification in sailors, and later instituted dietary reforms in the Japanese Navy, which largely eradicated beriberi from the Japanese Navy by 1887. In 1889 Eijkman in Java serendipitously identified dietary factors as a major contributor to "chicken polyneuritis," which he took to be an animal model for beriberi; the polyneuritis could be cured or prevented by feeding the chickens either unpolished rice or rice polishings. By 1901, Grijns, while continuing studies of beriberi in Java, suggested a dietary deficiency explanation for beriberi after systematically eliminating deficiencies of known dietary components and excluding a toxic effect. Wernicke-Korsakoff syndrome: In the late 1870s, Wernicke identified a clinicopathological condition with ophthalmoparesis, nystagmus, ataxia, and encephalopathy, associated with punctate hemorrhages symmetrically arranged in the grey matter around the third and fourth ventricles and the aqueduct of Sylvius. In the late 1880s, Korsakoff described a spectrum of cognitive disorders, including a confabulatory amnestic state following an agitated delirium, occurring in conjunction with peripheral polyneuropathy. Beginning around 1900, investigators recognized the close relationship between Korsakoff's psychosis, delirium tremens, and Wernicke's encephalopathy, but not until several decades later were Wernicke's encephalopathy, Korsakoff's psychosis, and beriberi all linked to the deficiency of a specific dietary factor, i.e. thiamin. Thiamin: Thiamin was crystallized from rice polishings by Jansen and Donath in 1926, and synthesized by Williams and Cline in 1936. In the late 1930s and early 1940s, characteristic pathological changes of Wernicke-Korsakoff syndrome were produced in animal models, the biochemical roles of thiamin in intermediary carbohydrate metabolism were elaborated by Peters and others, and the therapeutic benefits of thiamin for Wernicke-Korsakoff syndrome and beriberi were demonstrated. By the 1950s synthetic forms of the vitamin were produced cheaply, allowing both therapeutic administration and prevention with food enrichment. Pellagra and niacin: Pellagra was unknown prior to the introduction of maize into Europe from the New World. In the 18th century, Casàl and Frapolli described the clinical features of pellagra in Europe, and linked it with poverty and subsistence on nutritionally marginal corn-based diets. In the United States, pellagra became epidemic among poor Southerners in the early 20th century, in part because of economically-driven reliance on monotonous, nutritionally inadequate diets, combined with new manufacturing methods that removed vitamins from processed grain. From 1914-1929, Goldberger completed well-designed epidemiologic investigations, tested theories with human experiments, and utilized an animal model ("black tongue" in dogs) - all strongly supporting a dietary deficiency explanation for pellagra over prevailing toxic and infectious theories. Initial prevention and treatment approaches proved inadequate because of complex social issues linked to poverty, even after Goldberger and colleagues established that dried brewer's yeast could cure or prevent pellagra less expensively than dietary modification. During the depression, the collapse of cotton as an economically viable crop facilitated crop diversification, which contributed to an abrupt decline in pellagra mortality in the early 1930s. In 1937 Elvehjem isolated the P-P (pellagra preventive) factor, identified it as nicotinic acid (niacin), and demonstrated that nicotinic acid and nicotinic acid amide cure black tongue in dogs. Although clinical trials soon confirmed dramatic therapeutic effects in individual people, therapeutic administration of niacin had relatively little impact on population-level morbidity and mortality. Vitamin fortification of foodstuffs during World War II ultimately eradicated endemic pellagra in the United States. In the 1940s and 1950s, with expanded biochemical knowledge, pellagra was reformulated as a deficiency disease due to inadequate niacin and its amino acid precursor tryptophan. Neural tube defects and folate: Folate deficiency was initially recognized clinically as a macrocytic anemia in the 1920s, and only clearly separated from pernicious anemia by the mid-20th century. When folic acid was isolated and synthesized in the 1940s, it was shown to correct the macrocytic anemia associated with pernicious anemia, while the neurological manifestations progressed. In the 1950s and 1960s, the biochemical role of folates in transferring single carbon units was elucidated. Beginning in the 1960s, folate deficiency was increasingly recognized as the major cause of preventable neural tube defects. In the early 1990s well-designed randomized trials established that folate supplementation could prevent neural tube defects. Trial data, collectively indicating that periconceptual folate administration reduces both the occurrence and recurrence risks of neural tube defects by at least 70%, helped establish governmental recommendations concerning folic acid intake and health policy concerning vitamin fortification of foodstuffs. When dietary modification and supplementation strategies proved inadequate, folic acid food fortification was legally mandated in the US in the late 1990s, which significantly improved population folate status and produced an abrupt decline (20%-27%) in the prevalence of neural tube defects at birth. Recent studies have established genetic predispositions for neural tube defects, including both infant and maternal gene polymorphisms for enzymes involved in folate-dependent homocysteine metabolism, which help explain how the genotype of the mother, the genotype of the unborn child, and environmental factors (e.g. folate intake) can all impact on the risk of neural tube defects. Subacute combined degeneration and B(12) deficiency: Pernicious anemia was recognized clinically in the mid-19th century by Addison, but the most important neurological manifestation - subacute combined degeneration of the spinal cord - was not recognized clinically and linked with pernicious anemia until the end of the 19th century, particularly by Lichtheim, Putnam, and Dana. At the beginning of the 20th century, pernicious anemia and the associated subacute combined degeneration of the spinal cord were considered, by many investigators, to result from infectious or toxic causes. During the first quarter of the 20th century, various therapies were employed, but, with the possible exception of transfusion, were largely ineffective. In the 1920s, Minot and Murphy showed that large quantities of ingested liver could be used to effectively treat pernicious anemia, and specifically could improve or prevent progression of neurological manifestations, and could extend life expectancy beyond 2 years. Beginning in the late 1920s, Castle demonstrated that a substance elaborated by the gastric mucosa ("intrinsic factor") was essential for the absorption of a dietary factor ("extrinsic factor," later shown to be vitamin B(12)) needed to prevent pernicious anemia. Over two decades, from the late 1920s until the late 1940s, increasingly potent liver extracts were manufactured that could be given either intramuscularly or intravenously. In 1947, vitamin B(12) was isolated by Folkers and colleagues, and nearly simultaneously by Smith. Shortly thereafter the therapeutic efficacy of vitamin B(12) on subacute combined degeneration was demonstrated by West and Reisner and others. By 1955, Hodgkin determined the molecular structure of cyanocobalamin using computer-assisted x-ray crystallography, allowing complete chemical synthesis of vitamin B(12) in 1960 by an international consortium. Beginning in the late 1950s, the absorption and biochemistry of vitamin B(12) were elaborated, and several lines of evidence converged to support an autoimmune basis for pernicious anemia.

Pregnancy outcome in ethanol-treated mice with folic acid supplementation in saccharose

INTRODUCTION

Maternal folic acid deficiency is the most important metabolic factor in the etiology of neural tube defects (NTD) and is reduced by ethanol, which is extensively consumed by young women.

OBJECTIVE

The objective of the study was to determine whether folic acid supplementation in dietary saccharose is efficient in the prevention NTD induced by ethanol in fetuses of Swiss mice.

MATERIALS AND METHODS

Pregnant mice were divided into four groups of six animals each: control (C), ethanol (E), deficient-supplemented (DS), and deficient-supplemented + ethanol (DSE). Groups C and E received commercial mouse chow (containing 3 mg/kg folic acid) throughout the experiment, while groups DS and DSE received a folic acid-free diet with the addition of saccharose supplemented with folic acid (2 mg/kg folic acid) in water. Group E and DSE animals received ethanol (4 g/kg) administered intraperitoneally from the seventh to the ninth gestational day (gd) and were euthanized on the 18th gd, while groups C and DS received saline.

RESULTS

Congenital anomalies were observed in groups E and DSE. The fetal weight and length of the animals in group E were lower than in groups C and DS and, in group DSE, were lower than in groups C and DS. The placental diameter of group E was smaller than that of group C, and the placental weight of group C animals was lower than that of groups E, DSE, and DS.

CONCLUSION

The study demonstrated that dietary supplementation with folate in saccharose is an accessible means of consumption that could be further diffused but in an increased dose than recommended to reduce the teratogenic effects of ethanol.

A systematic review of dietary assessments of pregnant adolescents in industrialised countries

Adolescent pregnancy is a major public health challenge for many industrialised countries and is associated with significant medical, nutritional, social and economic risk for mothers and their infants. Despite this, relatively little is known about the nutrient intakes of adolescents during pregnancy. The aim of this study is to review the current evidence relating to the dietary assessment of pregnant adolescents living in industrialised countries. Nine papers were identified that fulfilled the inclusion criteria, seven of which were conducted in the USA. Mean nutrient intakes were compared with the most recent US dietary reference intakes (DRI) for pregnant adolescents. Despite the poor quality of the majority of studies, there appeared to be some consensus to suggest that the nutrient intakes of pregnant adolescents were below the DRI for energy, iron, folate, calcium, vitamin E and magnesium, nutrients which are recognised to be vital for fetal growth and development during pregnancy. Modest differences were observed in nutrient intake between trimesters and age groups. Current research is limited by sampling and measurement bias, and research is urgently required to address these limitations. Further consideration should also be made of the influence of age and of role of socio-economic support on pregnant adolescents' nutrient intake. The achievement of improved nutrition in pregnancy among adolescents requires multidisciplinary collaborations of adolescent health care providers, academics, professional organisations, policy makers, industry and service users. Only once this is achieved can adolescent nutrition, and adolescent nutrition in pregnancy, be significantly and sustainably optimised.

Childbearing women of twenty and under are at greater risk than those of twenty-five and over for compromised folate status

This study assessed folate intakes, folate concentrations in plasma and erythrocytes, plasma total homocysteine (tHcy) concentration, and urinary excretion of folate metabolites in Korean women with childbearing potential. A total of 23 women voluntarily participated in this study. Precise dietary intakes for 3 consecutive days were determined by weighing all foods consumed and folate intake was calculated using a computer-aided dietary analysis system. Folate concentration of plasma and erythrocytes was determined by a microbiological method. Plasma tHcy concentration was assayed using an HPLC analysis method. Urine excreted over the same period of time was collected and folate catabolites, para-aminobenzoylglutamate (pABG) and para-acetamidobenzoylglutamate (ApABG), were evaluated using a reverse-phase HPLC method after affinity chromatography. Young women of 20 and under were likely to consume less folate with low energy intake, had lower folate concentration in plasma and erythrocytes, and excreted a lesser amount of ApABG and total folate catabolites than women of 25 years and over. The results of this study confirmed that young Korean women with childbearing potential, especially those under 21 years of age, might be at risk for compromised folate status due to insufficient folate intakes from inadequate energy consumption.

Red blood cell folate concentrations increase more after supplementation with [6S]-5-methyltetrahydrofolate than with folic acid in women of childbearing age

BACKGROUND

For the primary prevention of neural tube defects (NTDs), public health authorities recommend women of childbearing age to take 400 mug folic acid/d 4 wk before conception and during the first trimester. The biologically active derivate [6S]-5-methyltetrahydrofolate ([6S]-5-MTHF) could be an alternative to folic acid.

OBJECTIVE

We investigated the effect of supplementation with [6S]-5-MTHF compared with that of folic acid on red blood cell folate concentration, an indicator of folate status.

DESIGN

The study was designed as a double-blind, randomized, placebo-controlled intervention trial. Healthy women (n = 144) aged 19-33 y received 400 microg folic acid, the equimolar amount of [6S]-5-MTHF (416 microg), 208 microg [6S]-5-MTHF, or placebo as a daily supplement for 24 wk. Red blood cell and plasma folate concentrations were measured at baseline and at 4-wk intervals.

RESULTS

The increase in red blood cell folate over time was significantly higher in the group receiving 416 microg [6S]-5-MTHF/d than in the groups receiving 400 microg folic acid/d or 208 microg [6S]-5-MTHF/d (P < 0.001). No plateau was reached in red blood cell folate concentration in the 3 treatment groups during 24 wk of intervention; however, plasma folate plateaued after 12 wk.

CONCLUSIONS

We showed that administration of [6S]-5-MTHF is more effective than is folic acid supplementation at improving folate status. In addition, the study indicates that the recommended period for preconceptional folic acid supplementation should be extended to >4 wk for maximal prevention of NTDs based on folate concentrations. [6S]-5-MTHF might be an efficient and safe alternative to folic acid.

Use of periconceptional folic acid supplements in Victoria and New South Wales, Australia

OBJECTIVES

To determine the proportion of women who took folate supplementation prior to conception and in the first three months of pregnancy and/or increased folate dietary intake; to determine how folate supplementation varied with socio-demographic factors; and to describe the ways women had seen or heard about folate prior to pregnancy.

METHODS

Two population-based surveys were used: the Victorian Survey of Recent Mothers 2000 and the 2001 NSW Child Health Survey.

RESULTS

Thirty-six per cent of women in Victoria reported taking periconceptional folate supplements compared with 46% in NSW. In Victoria, 8%, and in NSW, 28% of women had increased dietary folate intake. In both surveys younger women, women with less education, less income, of non-English speaking background and women who were not married were less likely to take folate supplements in the recommended period. In Victoria, multiparous women were significantly less likely to take supplements. In NSW, women with an unplanned pregnancy and those living in rural areas were significantly less likely to take periconceptional folate supplements. Fifty-three per cent of women cited a general practitioner or obstetrician as a source of folate information and 45% cited family or friends; both of these sources were significantly associated with periconceptional folate supplementation.

CONCLUSIONS

Less than 50% of women took periconceptional folate supplements. Among socially disadvantaged groups, the proportion was significantly lower.

IMPLICATIONS

Since women are unlikely to achieve adequate folate intake periconceptionally without deliberate action, there remains the need for a multifaceted approach to providing women with information about folate. Future surveys are needed to monitor usage and knowledge.

A comparison of the dietary and total intake of micronutrients in a group of pregnant Greek women with the Dietary Reference Intakes

OBJECTIVE

We compared the dietary and total (diet and supplement) intake of micronutrients with the Dietary Reference Intakes (DRIs) from the USA in a population of pregnant Greek women.

METHODS

Two hundred pregnant women participated in a nutritional survey, 98 in the second trimester and 102 in the third trimester in a random sampling. To examine dietary intake we used two questionnaires, the nutritional questionnaire for pregnant women from the California Department of Health Services, and a semi-quantitative questionnaire (Walter Willet) with modifications for use in Greece. Dietary intake analysis was performed using the Diet Analysis Plus software, Version 3, ESHA Research. Statistical analysis was performed with Minitab for Windows, Release 12. A simple complementary questionnaire concerning demographic and socio-economic features was also completed.

RESULTS

The average total intake of vitamins A, B(1), B(2), B(3), B(6), B(12) and C, calcium and phosphorus was higher than the respective DRIs. Folic acid and iron intake exceed the highest values specified for pregnancy. Vitamin E and zinc was lower than the DRIs, while vitamin D, magnesium and thiamin did not differ.

CONCLUSIONS

The results of our study suggest that in a Greek population, sufficient micronutrients appear to be received in adequate amount from diet, except for folic acid and iron, which also had to be taken in the form of nutritional supplements.

Acute absorption of folic acid from a fortified low-fat spread

OBJECTIVE

To explore the feasibility of low-fat spreads as vehicles for folic acid (FA) fortification by determining the acute absorption of FA from a fortified spread.

DESIGN

Double blind, crossover study to test each of the following treatments administered at 1-weekly intervals: (A) 20 g low-fat (40%) spread fortified with 200 microg FA and a placebo tablet; (B) 20 g low-fat placebo spread and a 200 microg FA tablet; (C) 20 g low-fat placebo spread and a placebo tablet.

SUBJECTS

A total of 13 male volunteers, aged 31.8+/-13.2 y.

MAIN OUTCOME MEASURES

Plasma total folate concentrations, measured before and up to 10 h after each treatment (n=10 samples per treatment).

RESULTS

Plasma folate concentrations were significantly increased compared with baseline values 1 h after administration of the FA tablet, and 1.5 h after the FA spread, and remained significantly higher than the baseline values for up to 7 h after both treatments. The maximum plasma folate response (R(max)), corrected for baseline values and 'placebo response', was established between 1 and 3 h postprandially in response to both FA spread and FA tablet, and no significant difference in R(max) was found between the two treatments (13.4 vs 14.4 nmol/l, P=0.9). The acute absorption of FA from fortified spread relative to that from the tablet, calculated on the basis of area under the plasma folate response curve, was 67% (P=0.04).

CONCLUSION

The absorption of FA from fortified low-fat spread, although lower than from a tablet, is effective. These results suggest that low-fat spreads, typically associated with fat-soluble vitamin fortification, may also be considered feasible as vehicles for FA fortification.

Effect of prenatal exposure to ethanol on hepatic elongation factor-2 and proteome in 21 d old rats: protective effect of folic acid

In this article, we study the effects of ethanol intake during pregnancy and lactation on hepatic and pancreatic elongation factor-2 (EF-2) of 21 d old progeny. At the same time, the effect of ethanol on the level of other relevant hepatic proteins was determined using proteomic analysis. The results show that ethanol not only produces a general increase of protein oxidation, but also produces an important depletion of EF-2 and several other proteins. Among the hepatic proteins affected by ethanol, the concomitant supplementation with folic acid to alcoholic mother rats prevented EF-2, RhoGDI-1, ER-60 protease, and gelsolin depletion. This protective effect of folic acid may be related to its antioxidant properties and suggests that this vitamin may be useful in minimizing the effect of ethanol in the uterus and lactation exposure of the progeny.

Folate intake assessment: validation of a new approach

OBJECTIVE

To describe the performance characteristics and validate a folate-specific focused recall approach to estimating folate intake.

DESIGN

In a cross-sectional study, folate-specific recalls were used to estimate subjects' average daily folate intake from seven days of dietary recall over a one-month period. This estimate was compared to an estimate of the average daily folate intake obtained using the Fred Hutchinson Cancer Research Center Food Frequency Questionnaire (FFQ) and to plasma folate and homocysteine concentrations.

SUBJECTS

Subjects were women aged 21 to 47 years and were recruited from the university community. Thirty-three subjects were recruited, and 28 subjects completed the study.

INTERVENTION

After an initial clinic visit, during which a baseline blood sample was collected for measurement of plasma folate and total homocysteine concentrations, subjects participated in focused dietary recall interviews by telephone and/or Internet (e-mail). At the end of the month, subjects completed the FFQ. Main outcome measures The main outcome measures were to describe how well the focused recalls were able to describe relative dietary folate intake as compared to the FFQ and if the focused recall method estimate correlated with plasma folate and homocysteine concentrations. Statistical analyses Estimated folate intakes were ranked by tertiles using the two dietary assessment approaches and the rankings were compared. The Spearman correlation test was used to compare the focused recall and the FFQ dietary data to plasma folate and homocysteine concentrations.

RESULTS

Estimated folate intake inclusive of supplements was 411.4+/-192.8 (mean+/-SD) microg/day based on focused recalls and 458.5+/-221.5 microg/day based on the FFQ. Exclusive of supplements, estimated folate intake from the diet was 327.8+/-30.2 microg/day based on focused recalls and 373.5+/-155.6 microg/day based on the FFQ. The ranking comparison of focused recalls vs the FFQ demonstrated a concordance of 44% without supplements and 67% with supplements for the highest tertile, and 56% without supplements and 67% with supplements for the lowest tertile. Estimated folate intake based on focused recalls was correlated significantly with plasma homocysteine (r=-0.443, P<.02) and was marginally significantly correlated with plasma folate (r=0.354; P=.06) concentrations.

APPLICATIONS

A focused dietary recall approach is a useful method for collecting information on folate intake in women. Estimated folate intake based on the focused recall approach is reasonably correlated with plasma folate and total homocysteine concentrations even in this small sample of women. Accurate data on folate intake can form the basis of dietary counseling to increase intake of this important micronutrient in the target population of young women.

Validation of a semiquantitative food frequency questionnaire to assess folate status. Results discriminate a high-risk group of women residing on the Mexico-US border

BACKGROUND

The purpose of the study was to estimate dietary intake of folate in two groups of women from different economic backgrounds and to evaluate validity of the 5-day-weighed food registry (5-d-WFR) and Food Frequency Questionnaire (FFQ) using biological markers.

METHODS

A cross-sectional study was conducted in two samples of urban Mexican women: one represented the middle socioeconomic status (middle SES) and the other, low socioeconomic status (low SES). Middle SES included 34 women recruited from 1998 to 1999. Participants were between the ages of 18 and 32 years and were employed in the banking industry (middle SES) in the US-Mexican border city of Tijuana, Baja California. Low SES included 70 women between the ages of 18 and 35 years recruited during the year 2000. These women were receiving care at a primary health care center in Ensenada, Baja California Norte State, Mexico (low SES). Pearson correlations were calculated between folate intake among 5-day diet registry, FFQ, and biochemical indices. FFQ reproducibility was performed by Spearman correlation of each food item daily and of weekly intake.

RESULTS

Average folate intake in middle SES from 5-d-WFR was 210 microg +/- 171. Fifty four percent of participants had intakes <200 microg/daily. Average folate intake from FFQ was 223 +/- 78 microg/day. Pearson correlation between log transformed and within individually adjusted 5-d-WFR folate intakes and serum folate was 0.40 (p=0.02).

DISCUSSION

Mexican women of reproductive age living in the US-Mexican border State of Baja California are at very high risk of NTDs as a result of low folate intake and low serum folate and RBC folate concentrations.

Periconceptional use of folic acid supplements in Oslo

BACKGROUND

Periconceptional supplementation with folic acid has been shown to decrease the occurrence of neural tube defects (NTD). A daily supplement of 400 micro g folic acid from the month before pregnancy and the first 2 to 3 months of pregnancy is recommended in Norway. We wanted to evaluate the use of folic acid supplements among pregnant women in Oslo, and to explore demographic factors that were associated with periconceptional intake.

METHODS

All women attending antenatal ultrasound screening at the two main obstetric departments in Oslo during 3 months in 2001 were invited to answer questions regarding folic acid supplementation before and during their present pregnancy.

RESULTS

A total of 1541 women (91, 5%) participated in the study, of which 26% were nonwestern immigrants. Only 17% of all women had started the folic acid supplementation preconceptionally (22% of the nonimmigrant vs. 2% of the immigrant population). Folic acid had been used by 58% at some time during the present pregnancy (73% of the nonimmigrant vs. 19% of the immigrant population). Regression analysis demonstrated that the difference in periconceptional use of folic acid between the two population groups could not be explained by registered demographic factors other than immigrant status.

CONCLUSIONS

Most pregnant women in Oslo do not use folic acid as recommended and a dramatically low usage is seen among the immigrant population, indicating that more widespread information is necessary. Furthermore, fortification of cereals with folic acid should be considered to secure a sufficient intake of folic acid in all fertile women.

Pregnancy, nutrition and parasitic diseases

In the developing world, young women, pregnant women, and their infants and children frequently experience a cycle where undernutrition (macronutrient and micronutrient) and repeated infection, including parasitic infections, lead to adverse consequences that can continue from one generation to the next. Among parasitic infections, malaria and intestinal helminths coexist widely with micronutrient deficiencies and contribute importantly to anemia and this cycle of retarded growth and development. In somewhat more limited or focal geographic settings, other parasitic diseases (e.g., schistosomiasis, filariasis) contribute similarly to this cycle. It is undoubtedly much better to enter a pregnancy free of infection and nutritionally replete than the various alternatives. Existing intervention strategies for micronutrient support and for the control of common parasitic infections before or during pregnancy, particularly malaria and intestinal helminths, should be followed. However, further research to identify barriers and priority approaches to achieving this goal remain very important in resource-poor settings where targeted public health efforts are required.

Folic acid and the prevention of neural tube defects (NTDs). Challenges and recommendations for public health

OBJECTIVE

To outline specific challenges facing public health in Canada that need to be addressed to ensure that all women of childbearing years can attain optimal folate status for prevention of NTDs.

METHODS

The new Dietary Reference Intake (DRI) for folate was examined in terms of the literature on the effective form of the vitamin, the level of folic acid provided by the Canadian food supply and the folic acid content of available supplements.

FINDINGS

There are six major challenges facing public health in Canada on this issue. These include confusion among health professionals and the general public on the effective form of the vitamin, requirements, and the necessity of taking supplements. Further obstacles to ensuring optimal folate status in all women of childbearing age in Canada include the limited amounts of folic acid that are currently permitted in foods and the difficulties involved in identifying the amount of folic acid provided in these foods in relation to needs.

INTERPRETATION

These challenges must be addressed to enable women in Canada to make an informed choice about folic acid. This has the potential to prevent up to 70% of the 300 births affected by NTDs each year.

A review of the MAFF Optimal Nutrition Status research programme: folate, iron and copper

OBJECTIVE

The objective was to conduct a critical appraisal of research conducted within one of the UK government's research programmes, Optimal Nutrition Status, and to place the findings of this work in the context of the international research effort, to assist policy makers and advisers. Nine nutrients are addressed within the programme; the findings for three of these are reported here: folate/folic acid, iron and copper.

DESIGN

To conduct the review, the researchers had access to all unpublished progress reports, submitted to officials, arising from the projects. The overall assessment criterion was whether the information generated by the research programme could be regarded as reliable experimental data of direct relevance to setting optimal dietary requirements for the particular micronutrients. However, findings were also assessed against specific scientific criteria concerning understanding of the bioavailability, interactions, development of functional markers and inter-individual variations in metabolism, for each of the nutrients scrutinised.

RESULTS

The results of the review indicated that many important questions are indeed being addressed by the UK government's research programme, and that the work is contributing to the overall research effort being conducted world-wide on this important subject.

CONCLUSIONS

Many major questions still need to be addressed before it will be possible to identify optimal intakes for various sub-populations. These priorities are summarised in the paper.

Modelling the potential impact of population-wide periconceptional folate/multivitamin supplementation on multiple births

OBJECTIVE

To develop a model of the impact of population-wide periconceptional folate supplementation on neural tube defects and twin births.

DESIGN

A hypothetical cohort of 100,000 pregnancies > or =20 weeks, plus terminations of pregnancy after prenatal diagnosis before 20 weeks.

METHODS

Application of pooled data on the relative risks for neural tube defects and twins following periconceptional folate from meta-analysis of the randomised trials.

MAIN OUTCOME MEASURES

1. Pregnancies with a neural tube defect (i.e. terminations of pregnancy, perinatal deaths, and surviving infants); 2. twin births (i.e. preterm births, perinatal deaths, postneonatal deaths, birth defects, cerebral palsy); 3. numbers needed to treat.

RESULTS

The change in neural tube defects would be 75 fewer terminations (95% CI -47, -90), 30 fewer perinatal deaths (95% CI 18, -35), and 13 fewer surviving infants with a neural tube defect (95% CI -8, -16). The change in twinning would be an additional 572 twin confinements (95% CI -100, +1587), among whom there would be 63 very preterm twin confinements (95% CI -11, +174), 54 perinatal and postneonatal deaths (95% CI -9, +149), 48 surviving twins with a birth defect (95% CI -8, +133), and nine with cerebral palsy (95% CI -2, +26). The numbers needed to treat for the prevention of one pregnancy with a neural tube defect is 847, for the birth of one additional set of twins is 175, for the birth of one additional set of very preterm twins is 1587, and for the birth of an additional twin with any of the following outcomes (perinatal death, postneonatal death, survival with a birth defect, or survival with cerebral palsy) is 901.

CONCLUSIONS

Monitoring rates of neural tube defects and twinning is essential as supplementation or fortification with folate is implemented.

Folate, homocysteine and neural tube defects: an overview

Folate administration substantially reduces the risk on neural tube detects (NTD). The interest for studying a disturbed homocysteine (Hcy) metabolism in relation to NTD was raised by the observation of elevated blood Hcy levels in mothers of a NTD child. This observation resulted in the examination of enzymes involved in the folate-dependent Hcy metabolism. Thus far, this has led to the identification of the first and likely a second genetic risk factor for NTD. The C677T and A1298C mutations in the methylenetetrahydrofolate reductase (MTHFR) gene are associated with an increased risk of NTD and cause elevated Hcy concentrations. These levels can be normalized by additional folate intake. Thus, a dysfunctional MTHFR partly explains the observed elevated Hcy levels in women with NTD pregnancies and also, in part, the protective effect of folate on NTD. Although the MTHFR polymorphisms are only moderate risk factors, population-wide they may account for an important part of the observed NTD prevalence.